1. Field of the Invention
The present invention relates to an image reading apparatus and an image formation system.
2. Description of Related Art
In general, an electrophotographic image forming apparatus (such as a printer, a copy machine, and a fax machine) is configured to irradiate (expose) a charged photoconductor drum (image bearing member) with (to) laser light based on image data to form an electrostatic latent image on the surface of the photoconductor. The electrostatic latent image is then visualized by supplying toner from a developing device to the photoconductor drum on which the electrostatic latent image is formed, whereby a toner image is formed. Further, the toner image is directly or indirectly transferred to a sheet, and then heat and pressure are applied to the sheet at a fixing nip to form a toner image on the sheet.
Practical use of image formation systems in which the above-mentioned image forming apparatus and an image reading apparatus are connected with each other has been facilitated. The image reading apparatus reads a toner image formed on a sheet, and feeds back the read information to the image forming apparatus so as to correct the color, position, multiplying factor or the like of the toner image. In the image formation system, before the toner image intended by the user is output to a sheet, correction of the image quality is performed based on the information read by the image reading apparatus.
To be more specific, the correction of the image quality is performed in the image forming apparatus by feedback of the correction value calculated from the information of the image position and the color read by the image reading apparatus to the image forming apparatus. In this manner, at the time when the toner image intended by the user is output to a sheet, automatic correction of the image quality can be performed with high efficiency based on the read information of the reading section.
Incidentally, since the light emitting element in the reading section emits light or generates heat when a current is supplied to the element, the heat generated at the time of light emission is dissipated to the surroundings whose temperature is lower than that of the element. In this manner, the temperature of the light emitting element is reduced, and the light emission performance of the light emitting element is maintained.
In addition, in the reading section, a sheet having passed through the fixing nip is conveyed, and as a result the temperature in the apparatus tends to be increased with the heat of the sheet. When the temperature of the region around the light emitting element increases with the increased temperature in the apparatus, dissipation of the heat generated by the light emitting element becomes difficult. When the heat-dissipation performance of the light emitting element is low, the temperature of the light emitting element is not easily reduced, and the temperature of the light emitting element is saturated, thus degrading light emission performance. Therefore, it is desirable to cool the light emitting element such that the light emission performance of the light emitting element is maintained.
For example, Japanese Patent Application Laid-Open No. 2012-93391 discloses a configuration in which a fan for introducing external air, and a duct for the air introduced by the fan are provided for the purpose of reducing the temperature in the apparatus. With this configuration, the light emission performance of the light emitting element can be maintained by cooling the light emitting element with the external air.
However, when a fan for introducing the external air and a duct are provided as in the configuration disclosed in Japanese Patent Application Laid-Open No. 2012-93391, the size of the apparatus increases as a whole. To be more specific, for example, in the case of an array-type configuration in which a plurality of light emitting elements are disposed side by side in the sheet width direction, a sheet being conveyed and the light emitting element face each other, and the light emission ability of the light emitting elements is easily reduced under the influence of the heat dissipated from the sheet having passed through the fixing nip, and therefore the wind power of the fan is required to be increased to compensate the reduction of the light emission ability. Since the size of the cooling members such as the fan is required to be increased, the apparatus size may be further increased.
In addition, in the case of the array-type configuration, the light emitting element and a sheet being conveyed face each other, and therefore, when the wind for cooling the light emitting element is applied to the light emitting element, the wind may become a resistance against the conveyance of the sheet facing the light emitting element depending on the direction of the wind. When the duct is configured such that it has no influence on the feeding path, the apparatus size may be further increased.
In particular, in the case where reading sections configured to read toner images printed on the both sides of a sheet with high efficiency and disposed at positions corresponding to the front surface and the rear surface of the sheet such that the read information can be fed back to the image forming apparatus are provided in a configuration for double-sided printing, a duct is required to be provided for each reading section, and the apparatus size is further increased.